Quantitative NMR (qNMR) is an analytical technique that has been developed to establish, among other things, the purity of organic compounds, as well as the level of actives in natural products, and in formulations. There are many reasons why 1H is the nucleus of choice and continues to be used: its ubiquity, its selectivity, its high sensitivity and resolution. 19F, 31P and more recently, 13C, have also been used to excellent effect, which demonstrates that the selectivity of this technique is widening its appeal and applicability, rivaling the more common analytical stalwarts, HPLC and GC.
There are other nuclei, however, which have been largely overlooked because they are low in frequency and sensitivity, and are subject to line broadening that may make their use for quantitation difficult. These features may preclude wider exploitation, such as with 33S, 35Cl [1] and 14N, although some effort has been made with oxygenates in fuels using 17O[2].
In this presentation, we will focus on optimizing experimental conditions best suited to situations where 17O can be successfully used for quantitation, in spite of its immediate drawbacks. One such situation is in the assessment of, for example, oxygenates in petrols such as E10, or the quantitation of ethanol in spiritous liquors.